Graph those points given, in a cartesian plane grid, that is, an x,y axis grid
and try to make a straight line from the leftmost, to the rightmost, they don't really line up as a straight line, so... try to draw a line that will cover "most of the points", there will be a couple or so "outliers", the line that "covers most of the points" is so-called "best-fit" line, so, using that line, try to get what "y" is, when x = 3
